Add 64-bit capability support to the kernel

The patch supports legacy (32-bit) capability userspace, and where possible
translates 32-bit capabilities to/from userspace and the VFS to 64-bit
kernel space capabilities.  If a capability set cannot be compressed into
32-bits for consumption by user space, the system call fails, with -ERANGE.

FWIW libcap-2.00 supports this change (and earlier capability formats)

 http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/

[akpm@linux-foundation.org: coding-syle fixes]
[akpm@linux-foundation.org: use get_task_comm()]
[ezk@cs.sunysb.edu: build fix]
[akpm@linux-foundation.org: do not initialise statics to 0 or NULL]
[akpm@linux-foundation.org: unused var]
[serue@us.ibm.com: export __cap_ symbols]
Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 96473b482099..320d74e707af 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -125,8 +125,7 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
          * Superuser processes are usually more important, so we make it
          * less likely that we kill those.
          */
-        if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_ADMIN) ||
-                                p->uid == 0 || p->euid == 0)
+        if (__capable(p, CAP_SYS_ADMIN) || p->uid == 0 || p->euid == 0)
                 points /= 4;
 
         /*
@@ -135,7 +134,7 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
          * tend to only have this flag set on applications they think
          * of as important.
          */
-        if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO))
+        if (__capable(p, CAP_SYS_RAWIO))
                 points /= 4;
 
         /*